Acute Kidney Injury After CT in Emergency Patients with Chronic Kidney Disease: A Propensity Score-matched Analysis

Comparison of value of 640-slice CT kidney scan and kidney ultrasound in the diagnosis of chronic kidney disease

To explore the value of 640-slice CT kidney scan and kidney ultrasound (KUS) in the diagnosis of chronic kidney disease (CKD). The data of 120 CKD patients at our institution between June 2019 and September 2020 were analyzed, and they were randomly divided into ultrasound (US) group (n = 40, KUS), CT group (n = 40) first receiving a plane CT scan to determine the scope of dynamic volume scan, which was performed for scans in cortical, parenchymal, and delayed phases with bolus injection of contrast medium, and combined group (n = 40, KUS and 640-slice CT kidney scan), with the images obtained read and analyzed. The subjective scores and effective radiation doses of 640-layer CT kidney scan were counted to calculate the detection rates. The subjective scores of 640-slice CT kidney scan in plane scan, cortical phase, parenchymal phase, and delayed phase were (1.23 ± 0.42), (1.80 ± 0.40), (2.08 ± 0.26), (2.18 ± 0.38) in the CT group and (1.18 ± 0.38), (1.85 ± 0.36), (2.08 ± 0.26), (2.20 ± 0.40) in the combined group. The effective radiation doses in the CT and combined groups were (1.92 ± 0.32) mSv and (1.95 ± 0.35) mSv. The reading results showed that 26 cases (65.0%), 30 cases (75.0%), and 38 cases (95.0%) were detected in the US, CT and combined groups, respectively, with remarkably higher detection rate in the combined group than the US and CT groups (P < 0.05). 640-slice CT kidney scan and KUS can be adopted for the diagnosis of CKD; with low radiation dose, good image quality, and higher detection rate in the former, their combination can improve the clinical detection rate of CKD and is worth promoting.

Iodinated Contrast and Nephropathy: Does It Exist and What Is the Actual Evidence?

Iodinated contrast material (ICM) is a critical component for many radiologic examinations and procedures. However, ICM has often been withheld in the past out of concern for its potential nephrotoxicity and increased risk of morbidity and mortality, often at the expense of diagnostic accuracy and timely diagnosis. Evidence from controlled studies now suggest that most cases of acute kidney injury (AKI) caused by ICM were instead due to contrast-independent causes of AKI or normal variation in renal function. This study will discuss current knowledge of contrast-induced AKI, including the incidence, sequelae, risk factors, and prevention strategies of this potential complication.

A deep learning algorithm for the detection of aortic dissection on non-contrast-enhanced computed tomography via the identification and segmentation of the true and false lumens of the aorta

Background

Aortic dissection is a life-threatening clinical emergency, but it is often missed and misdiagnosed due to the limitations of diagnostic technology. In this study, we developed a deep learning-based algorithm for identifying the true and false lumens in the aorta on non-contrast-enhanced computed tomography (NCE-CT) scans and to ascertain the presence of aortic dissection. Additionally, we compared the diagnostic performance of this algorithm with that of radiologists in detecting aortic dissection.

Methods

We included 320 patients with suspected acute aortic syndrome from three centers (Beijing Anzhen Hospital Affiliated to Capital Medical University, Fujian Provincial Hospital, and Xiangya Hospital of Central South University) between May 2020 and May 2022 in this retrospective study. All patients underwent simultaneous NCE-CT and contrast-enhanced CT (CE-CT). The cohort comprised 160 patients with aortic dissection and 160 without aortic dissection. A deep learning algorithm, three-dimensional (3D) full-resolution U-Net, was continuously trained and refined to segment the true and false lumens of the aorta to determine the presence of aortic dissection. The algorithm's efficacy in detecting dissections was evaluated using the receiver operating characteristic (ROC) curve, including the area under the curve (AUC), sensitivity, and specificity. Furthermore, a comparative analysis of the diagnostic capabilities between our algorithm and three radiologists was conducted.

Results

In diagnosing aortic dissection using NCE-CT images, the developed algorithm demonstrated an accuracy of 93.8% [95% confidence interval (CI): 89.8-98.3%], a sensitivity of 91.6% (95% CI: 86.7-95.8%), and a specificity of 95.6% (95% CI: 91.2-99.3%). In contrast, the radiologists achieved an accuracy of 88.8% (95% CI: 83.5-94.1%), a sensitivity of 90.6% (95% CI: 83.5-94.1%), and a specificity of 94.1% (95% CI: 72.9-97.6%). There was no significant difference between the algorithm's performance and radiologists' mean performance in accuracy, sensitivity, or specificity (P>0.05).

Conclusions

The algorithm proficiently segments the true and false lumens in aortic NCE-CT images, exhibiting diagnostic capabilities comparable to those of radiologists in detecting aortic dissection. This suggests that the algorithm could reduce misdiagnoses in clinical practice, thereby enhancing patient care.

Association Between IV Contrast Media Exposure and Acute Kidney Injury in Patients Requiring Emergency Admission: A Nationwide Observational Study in Japan

OBJECTIVE

This study aimed to elucidate the association between IV contrast media CT and acute kidney injury (AKI) and in-hospital mortality among patients requiring emergency admission.

DESIGN

In this retrospective observational study, we examined AKI within 48 hours after CT, renal replacement therapy (RRT) dependence at discharge, and in-hospital mortality in patients undergoing contrast-enhanced CT or nonenhanced CT. We performed 1:1 propensity score matching to adjust for confounders in the association between IV contrast media use and outcomes. Subgroup analyses were performed according to age, sex, diagnosis at admission, ICU admission, and preexisting chronic kidney disease (CKD).

SETTING AND PATIENTS

This study used the Medical Data Vision database between 2008 and 2019. This database is Japan's largest commercially available hospital-based claims database, covering about 45% of acute-care hospitals in Japan, and it also records laboratory results.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The study included 144,149 patients with (49,057) and without (95,092) contrast media exposure, from which 43,367 propensity score-matched pairs were generated. Between the propensity score-matched groups of overall patients, exposure to contrast media showed no significant risk of AKI (4.6% vs. 5.1%; odds ratio [OR], 0.899; 95% CI, 0.845-0.958) or significant risk of RRT dependence (0.6% vs. 0.4%; OR, 1.297; 95% CI, 1.070-1.574) and significant benefit for in-hospital mortality (5.4% vs. 6.5%; OR, 0.821; 95% CI, 0.775-0.869). In subgroup analyses regarding preexisting CKD, exposure to contrast media was a significant risk for AKI in patients with CKD but not in those without CKD.

CONCLUSIONS

In this large-scale observational study, IV contrast media was not associated with an increased risk of AKI but concurrently showed beneficial effects on in-hospital mortality among patients requiring emergency admission.

Risk of Acute Kidney Injury Following IV Iodinated Contrast Media Exposure: 2023 Update, From the AJR Special Series on Contrast Media

Iodinated contrast material (ICM) has revolutionized the field of diagnostic radiology through improvements in diagnostic performance and the expansion of clinical indications for radiographic and CT examinations. Historically, nephrotoxicity was a feared complication of ICM use, thought to be associated with a significant risk of morbidity and mortality. Such fears often precluded the use of ICM in imaging evaluations, commonly at the expense of diagnostic performance and timely diagnosis. Over the past 20 years, the nephrotoxic risk of ICM has become a topic of debate, as more recent evidence from higher-quality studies now suggests that many cases of what was considered contrast-induced acute kidney injury (CI-AKI) likely were cases of mistaken causal attribution; most of these cases represented either acute kidney injury (AKI) caused by any of myriad other known factors that can adversely affect renal function and were coincidentally present at the time of contrast media exposure (termed "contrast-associated AKI" [CA-AKI]) or a manifestation of the normal variation in renal function that increases with worsening renal function. This Special Series Review discusses the current state of knowledge regarding CI-AKI and CA-AKI, including the incidence, risk factors, outcomes, and prophylactic strategies in the identification and management of these clinical conditions.

Effect of Missed Post-Procedure Creatinine Measurement on Sub-Acute Kidney Injury Following Coronary Angiography

Serum creatinine (SCr) levels are essential for the diagnosis of kidney disease after coronary angiography (CAG). However, the influence of missed post-procedure SCr measurement in this situation is unclear. The present study included 14,127 patients undergoing CAG as part of the Cardiorenal ImprovemeNt registry II. Patients were divided into two groups according to whether a post-procedure SCr was measured within 3 days. The primary endpoint was acute kidney disease (AKD). Logistic regression was used to evaluate the relationship between post-procedure SCr and AKD. Of the 14,127 patients (61.6 ± 9.8 years, 34.2% females), 55.4% (n = 7822) did not have a post-procedure SCr measurement. The incidence of AKD was higher in the missed post-procedure SCr group (15.7 vs 11.9%; median follow-up 6.54 years). Multivariate logistic regression showed that missed post-procedure SCr measurement was associated with significantly higher risk of AKD (adjusted odds ratio [aOR]: 1.26, 95% CI: 1.10-1.45, P < .001). The results were more significant in patients with normal renal function at baseline (aOR: 1.36, 95% CI: 1.16-1.60, P < .001). In our study, over half of the patients undergoing CAG missed their post-procedure SCr measurement. The missed post-procedure SCr group had a significantly higher risk of developing AKD compared with those with a post-procedure SCr measurement.

Changes in renal function over time in outpatients with eGFR ≥ 30 mL/min/1.73 m2: implication for timing of renal function testing before contrast-enhanced CT imaging

PURPOSE

To evaluate the associations between comorbidities and kidney function decline at 6-month and 1-year follow-up in outpatients with initial estimated glomerular filtration rate (eGFR) ≥ 30 mL/min/1.73 m2.

MATERIALS AND METHODS

Outpatients aged 18 and older with confirmed diagnosis, who had eGFR ≥ 30 mL/min/1.73 m2 measured between April 2017 and March 2019, were included in this retrospective observational study. Of them, 30,595 included outpatients had 6-month eGFR test and 27,698 included outpatients had 1-year eGFR test. The outpatients were further divided into two groups based on initial eGFR: between 30 and 59 and ≥ 60 mL/min/1.73 m2. Impaired renal function was defined as eGFR declined to below 30 mL/min/1.73 m2. The comorbidities with P values less than 0.1 identified in univariable logistic regression models were entered into the multivariable analysis with backward selection, thereby identifying comorbidities that increased the risk of eGFR decline at 6-month and 1-year follow-up.

RESULTS

Outpatients with initial eGFR between 30 and 59 mL/min/1.73 m2 were 175.94 times more likely to have eGFR decline at 6 months, and were 94.10 times more likely to have eGFR decline at 1 year, compared with their corresponding initial eGFR ≥ 60 counterparts. Multivariable logistic regression analyses disclosed that chronic kidney disease, hypertension, and heart failure were independent risk factors for eGFR decline in outpatients with initial eGFR between 30 and 59 mL/min/1.73 m2.

CONCLUSIONS

Outpatients with initial eGFR ≥ 60 mL/min/1.73 m2 might not need routine eGFR test prior to contrast-enhanced CT scan for 1 year. In addition, chronic kidney disease, hypertension, and heart failure increased the risk of declined renal function, particularly, in outpatients with initial eGFR between 30 and 59 mL/min/1.73 m2.

Illuminating the Use of Trauma Whole-Body CT Scan During the Global Contrast Shortage

BACKGROUND

Use of whole-body CT scan (WBCT) is widespread in the evaluation of traumatically injured patients and may be associated with improved survival. WBCT protocols include the use of IV contrast unless there is a contraindication. This study tests the hypothesis that using plain WBCT scan during the global contrast shortage would result in greater need for repeat contrast-enhanced CT, but would not impact mortality, missed injuries, or rates of acute kidney injury (AKI).

STUDY DESIGN

All trauma encounters at an academic level-I trauma center between March 1, 2022 and June 24, 2022, excluding burns and prehospital cardiac arrests, were reviewed. Imaging practices and outcomes before and during contrast shortage (beginning May 3, 2022) were compared.

RESULTS

The study population included 1,109 consecutive patients (72% male), with 890 (80%) blunt and 219 (20%) penetrating traumas. Overall, 53% of patients underwent WBCT and contrast was administered to 73%. The overall rate of AKI was 6% and the rate of renal replacement therapy (RRT) was 1%. Contrast usage in WBCT was 99% before and 40% during the shortage (p < 0.001). There was no difference in the rate of repeat CT scans, missed injuries, AKI, RRT, or mortality.

CONCLUSIONS

Trauma imaging practices at our center changed during the global contrast shortage; the use of contrast decreased despite the frequency of trauma WBCT scans remaining the same. The rates of AKI and RRT did not change, suggesting that WBCT with contrast is insufficient to cause AKI. The missed injury rate was equivalent. Our data suggest similar outcomes can be achieved with selective IV contrast use during WBCT.

Comparison of Diagnostic Value for Chronic Kidney Disease between 640-Slice Computed Tomography Kidney Scan and Conventional Computed Tomography Scan

Objective

To explore the diagnostic value for chronic kidney disease (CKD) between 640-slice computed tomography (CT) kidney scan and conventional CT scan.

Methods

A total of 120 CKD patients who received kidney plain scan plus enhanced examination in the CT room of the Medical Imaging Department of our hospital from June 2019 to September 2019 were selected and randomly divided into the experimental group (n = 60) and the control group (n = 60). Patients in the control group received the conventional CT plain scan and enhanced scan, and for patients in the experimental group, CT plain scan was performed first, the range of 640-slice CT dynamic volume scan was determined, and after bolus injection of contrast agent, dynamic volume scan was performed for scanning in the cortical phase, myeloid phase, and secretory phase. The imaging quality and effective scanning dose were compared between the two modalities, and the relationship between CT values obtained from 640-slice CT scan and conventional CT scan and the renal impairment was analyzed.

Results

Compared with the control group, the image quality of 640-slice CT scan conducted in the experimental group was significantly better (P < 0.05); the effective radiation doses of the experimental group and the control group were, respectively, (1.89 ± 0.32) mSv and (3.26 ± 0.47) mSv, indicating that the dose was significantly lower in the experimental group than in the control group (t = 18.664, P < 0.001), and the correlation analysis showed that the relationship between the sum of CT values in the cortical phase of both kidneys and kidney injury in the experimental group was r = 0.835, P < 0.001.

Conclusion

Both 640-slice CT kidney scan and conventional CT scan can be used in the diagnosis of CKD. 640-slice CT has a lower radiation dose, better image quality, and higher application value.

Risk of acute kidney injury after contrast-enhanced computerized tomography: a systematic review and meta-analysis of 21 propensity score-matched cohort studies

OBJECTIVES

Intravenous application of contrast media is part of a wide spectrum of diagnostic procedures for better imaging quality. Clinical avoidance of contrast-enhanced imaging is an ever-present quandary in patients with impaired kidney function. The objective of this study was to estimate the risk for acute kidney injury (AKI), dialysis and mortality among patients undergoing contrast-enhanced CT compared to propensity score-matched controls (i.e. contrast-unenhanced CT). Selected cohort studies featured high-risk patients with advanced kidney disease and critical illness.

METHODS

This review was designed to conform to the Preferred Reporting Items in Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed was searched from August 2021 to November 2021 for all-language articles without date restriction. A random-effects model (DerSimonian and Laird method) was used for meta-analysis.

RESULTS

Twenty-one articles were included, comprising data of 169,455 patients. The overall risk of AKI was similar in the contrast-enhanced and unenhanced groups (OR: 0.97 [95% CI: 0.85; 1.11], p = 0.64), regardless of baseline renal function and underlying disease. Substantial heterogeneity was detected (I² = 90%, p ≤ 0.0001). Multivariable logistic regression identified hypertension (p = 0.03) and estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m² (p = 0.0001) as factors associated with greater risk of post-contrast AKI.

CONCLUSIONS

Based on propensity score-matched pairs obtained from 21 cohort studies, we found no evidence for increased risk for AKI, dialysis or mortality after contrast-enhanced CT among patients with eGFR ≥ 45 mL/min/1.73 m². In congruence with the emerging evidence in the literature, caution should be exercised in patients with hypertension and eGFR ≤ 30 mL/min/1.73 m².

KEY POINTS

• The application of contrast media for medical imaging is not associated with higher odds for AKI, induction of renal replacement therapy, or mortality. Many comorbidities traditionally associated with greater risk for acute kidney injury do not appear to predispose for renal decline after contrast media exposure. • Underlying hypertension and eGFR less than or equal to 30 mL/min/1.73 m² seem to predispose for post-contrast acute kidney injury. • Propensity score matching cannot account for unmeasured influences on AKI incidence, which needs to be addressed in the interpretation of results.

The Incidence and Associated Risk Factors of Contrast-Induced Nephropathy after Contrast-Enhanced Computed Tomography in the Emergency Setting: A Systematic Review

Iodinated contrast media (ICM) during contrast-enhanced computed tomography (CECT) in the emergency department (ED) is essential to diagnose acute conditions, despite risks of contrast-induced nephropathy (CIN) development and its associated complications. This systematic review aims to evaluate the incidence of CIN and CIN-induced complications, and to explore the relevance of classical risk factors for CIN among ED patients receiving ICM. PubMed, Cochrane, and Web of Science were used on 30 August 2021 to search for peer-reviewed English articles reporting on CIN incidence among ED patients aged ≥18 years who underwent an intravenous CECT. The inclusion criteria included studies that were in English, peer-reviewed, and involved ED patients aged ≥18 years who underwent single intravenous CECT. Studies on intra-arterial procedures and preventive strategies, meta-analyses, clinical guidelines, review articles, and case reports were excluded. The JBI critical appraisal checklist was applied to assess the risk of bias. In total, 18 studies were included wherein 15 were retrospective studies while three were prospective studies. We found a relatively higher CIN incidence in the ED, with variations owing to the CIN definitions. Several classical risk factors including acute hypotension remain linked to CIN onset in ED settings unlike factors such as age and diabetes. While risk of adverse renal events due to CIN is low, there is higher risk of CIN-induced mortality in the ED. Therefore, with the higher incidence of CIN and CIN-induced mortality rates in the ED, ICM administration during CECT in the ED should still be clinically justified after assessing both benefits and risks.